Really stupid question about Base Stations

Forgive an old man but I'm trying to understand how this works -- if the base stations aren't plugged in to anything other than power, what the heck are they actually doing? I understand I'll be putting dongles in the USB ports of the PC for controllers and trackers (I'm going to use this stuff for animation, with IKinema Orion) but how the heck is a base station actually working? I assume what it's doing is communicating both ways -- getting signals from the trackers/controllers and then, what, sending them back through those same things to my PC?

This stuff is making my head hurt but I really would like to know other than "it's magic".